Fluid couplings capable of interconnecting conduits in a manner wherein vibrations within the conduits are absorbed or damped are commonly used in those applications wherein the sound generated by fluid flow, conduit expansion and other vibration producing origins is objectionable. For instance, submarines and other warships widely employ vibration attenuating couplings to minimize the likelihood of detection. Further, it is advantageous to utilize couplings in a conduit system capable of accommodating conduit misalignment, and conduits having limited flexibility for alignment or vibration attenuating purposes are highly desirable.
Flexible and vibration attenuating couplings are known wherein elastomeric elements are used between the coupling components for vibration absorbing purposes. For instance, the United States Navy utilizes rubber insert sound isolation couplings on warships to provide piping flexibility and sound vibration absorption and other couplings employed annular elastomer gaskets intermediate a coupling housing and nipple wherein the gaskets were placed under compression by a nut threaded into the housing. Further, flexible pipe connections of the aforementioned type are shown in U.S. Pat. Nos. 3,390,889; 3,734,546; 3,853,337; 4,068,864 and 4,076,284.
In the patents listed above it is known to interconnect major coupling components by the use of an elastomeric outer bearing interposed between a housing and nipple wherein ends of the outer bearing are bonded to collars, one of the collars being attached to housing structure while the other collar engages the coupling nipple. Also, these patents disclose arrangements wherein inner bearing structure supports the nipple relative to the housing at a location remote from the outer bearing. Such known constructions absorb sound producing vibrations as well as provide a limited degree of flexibility between interconnected conduits.
Couplings employing an elastomeric outer bearing having bonded collars and an inner bearing are superior in vibration absorbing characteristics, flexibility accommodation and longevity to couplings employing elastomeric gaskets under compression. However, as gasket type couplings have long been used it is impractical from a cost standpoint to replace such couplings in their entirety with elastomeric outer and inner bearing type couplings, and it is an object of the invention to provide a vibration absorbing coupling construction wherein major existing coupling components may be utilized to minimize the cost of conversion and retrofit of such gasket type couplings to couplings employing outer and inner elastomeric bearings.
Another object of the invention is to provide a vibration attenuating fluid coupling wherein an existing coupling housing may be utilized without modification and only nipple and elastomeric components need be substituted to convert gasket type couplings to the bearing type.
Yet another object of the invention is to provide vibration attenuating coupling structure capable of converting a gasket type coupling to an inner and outer bearing type coupling wherein no machining of the existing coupling housing is required, and wherein the inner bearing cooperates with existing housing surfaces to maintain the inner bearing in location.
In the practice of the invention an existing gasket type coupling is disassembled, and the gaskets and nipple are replaced with inner and outer bearings and a nipple constructed in accord with the invention. An inner bearing of annular configuration is located within the housing and includes axial and radially extending surfaces complimentary in configuration and dimension to similar existing surfaces within the housing, and in this manner the inner bearing is accurately located and positioned within the coupling housing.
The inner bearing consists of a metallic ring exteriorly provided with an elastomeric material, the elastomer engaging the housing surfaces, and includes a convex surface having passages defined therein wherein the convex surface engages a bearing surface defined upon the nipple.
An outer bearing assembly consisting of an elastomeric ring internally reinforced by embedded metal rings includes metallic collars bonded thereto at each end of the elastomeric ring. One of these collars engages a nut threaded upon the coupling housing, while the other collar engages an oblique surface defined upon the inner end of the nipple.
Rotation of the nut causes the outer bearing to displace the nipple into engagement with the inner bearing, and the inner end of the nipple is thereby supported within the housing solely upon elastomeric material. The nipple includes an outer end extending from the housing, and a flange mounted upon the nipple outer end is of such configuration as to be attached to a conventional conduit. In this manner the coupling structure permits flexibility between the housing and nipple, and as the nipple is resiliently supported within the housing upon elastomeric material vibrations will not be transferred therebetween.